3 FeS + 16 HNO3 → 3 Fe(NO3)3 + 3 SO2 + 7 NO + 8 H2O
This is an oxidation-reduction (redox) reaction:
3 S-II - 18 e- → 3 SIV (oxidation)
7 NV + 21 e- → 7 NII (reduction)
3 FeII - 3 e- → 3 FeIII (oxidation)
FeS is a reducing agent, HNO3 is an oxidizing agent, FeS is a reducing agent.
Reactants:
- FeS
- HNO3 – Nitric acid
- Other names: Aqua fortis , Spirit of niter , Eau forte
- Appearance: Colorless, yellow or red fuming liquid ; Colourless-to-yellow liquid with pungent odour ; Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]
Products:
- Fe(NO3)3 – Iron(III) nitrate
- SO2 – Sulfur dioxide
- Other names: Sulfurous anhydride , Sulphur dioxide , Sulfurous acid anhydride
- Appearance: Colorless gas ; Colourless gas or compressed liquefied gas with pungent odour ; Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14°F. Shipped as a liquefied compressed gas.]
- NO – Nitrogen monoxide , Oxidonitrogen(•) (additive)
- H2O – Water, oxidane